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MHT CET202521 Apr 2025Morning ShiftChemistryThermodynamics (C)Actual

Find standard enthalpy of formation of ammonia from following reaction. N _ 2( ~g ) +3 H _ 2( ~g ) 2 NH _ 3( ~g ) ; _ r H ^0=-92.0 ~kJ

Options

  1. A-92.0 ~kJ ~mol ⁻¹
  2. B-69.0 ~kJ ~mol ⁻¹
  3. C-46.0 ~kJ ~mol ⁻¹
  4. D-184.0 ~kJ ~mol ⁻¹

Correct answer

C. -46.0 ~kJ ~mol ⁻¹

Step-by-step solution

The reaction N _ 2( g ) + 3 H _ 2( g ) 2 NH _ 3( g ) has an enthalpy change _ r H ^0 = -92.0 kJ for the formation of 2 moles of ammonia from its elements in standard states. Standard enthalpy of formation represents the enthalpy change per mole formed, so _ f H ^0 ( NH ₃) = -92.0 kJ 2 mol = -46.0 kJ mol⁻¹ . Final answer: C

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